'The Sing Off' Season 3 Winner Announced [VIDEO]

The Sing Off season 3 has declared its winner in the live finale Monday night.

The NBC singing competition crowned Pentatonix, a quintet from Austin, Texas, its final winner.

The group won a $200,000 grand prize plus a recording contract with Sony Music.

From the beginning, you guys blew me away ... and you continue to do it. Amazing, said judge Shawn Stockman of Boyz II Men.

I don't even know what to say, said Pentatonix member Scott Hoying. I can't believe it.

They were up against two other final competitiors - Urban Method and the Dartmouth Aires.

The group performed David Guetta and Usher's Without You. They also collaborated with former 98 Degrees front man and current Sing Off host Nick Lachey on Give Me Just One Night (Una Noche).

The show featured guest appearances by Smokey Robinson and rapper Flo Rida. Also in attendance were judges Ben Folds and Sara Bareilles, who were interviewed on the red carpet after the finale.

Nick Lachey spoke to the press after the show as well.

It was a great way to kind of wrap up the season with a live finale like that, said the host.

I couldn't be happier for Pentatonix's. They are so deserving.

He even talked about singing with the group for the last show.

Look, if no other group is going to cover 98 Degrees, I gotta do it myself. So finally after three seasons we got a little 98 Degrees love on the show. And it was fun, it was kind of a walk down memory lane. I hadn't sung that song in probably 10, 11 years.

Lachey's new wife was just as excited for the finale. The blushing bride Vanessa Lachey tweeted her anticipation before the show.